老秃顶子自然保护区存在的问题及对策

自然保护区的迅速发展提出了一个重要问题，即如何有效持续地管理这些保护区，这是各个保护区面临的一个重要问题。经过调查发现，经费不足是各保护区普温存在的问题。由于经费不足，各保护区纷纷利用自己的资源进行资源开发，特别是开展旅游，由开展旅游引发了一系列问题，其中资源浪费和生态环境恶化是保护区存在的最为严重的问题，也是亟需解决的问题。本文就如何进行可持续的保护与发展问题作了一些探讨，重点对老秃顶子自然保护区的环境容量问题做了预测。     

深化集体林权制度改革的实践和思考

集体林权制度改革开展5年多来，成效与作用十分显著。改革唤醒了林区、唤醒了林农、唤醒了务林者、唤醒了社会，使林区经济活起来、资源多起来、百姓富起来、林区稳起来。改革解决了产权问题，解决了动力问题；改革也使山区林区找到脱贫致富奔小康的路子，解决了新农村建设中生产力怎么发展的问题，解决了百姓的增收问题，它的意义远远超出了林改的本身，已上升为党和政府解决“三农”问题、解决山区问题的一个抓手。     

西部大开发中的生态环境建设问题：—代笔谈小结

本文是在《林业科学》上连续登载的“在西部大开发中的生态环境建设问题”笔谈的阶段小结。文中概略阐述了生态环境建设的概念和内涵，生态环境建设在西部大开发中的位置，提出了西部地区生态环境建设应遵循的６项原则，即因地制宜，因害设防；保护先行，善待自然；多样措施，林草为本；生态经济，密切结合；全面规划，综合治理，加大投入，群策群力，最后对当前生态环境建设中存在的及有不同看法的一些问题进行了分析探讨，这些问题包括：天然林保护工程的导向问题，退耕还林还草的选向问题，林草植被建设的方式和技术问题，以及生态环境建设与水资源的关系问题。     

工学硕士论文质量问题简析

近年来，研究生招生数量激增，随之而来的是研究生论文的质量也出现下降的趋势，论文中所暴露出来的问题也越来越多。该文在分析了近几年硕士论文的答辩材料基础上，对硕士论文中存在的问题做了分类阐述，对论文格式上的问题、论文中常识性的错误、实验研究中存在的问题、论文结构上的问题等做了简要分析，并将论文存在的缺陷分为两类，一类称之为软伤，另一类称之为硬伤。     

公路环境保护与绿化探讨

指出了随着公路里程以及汽车保有量的持续增长，公路污染及公路对周边环境的影响问题日益严重，结合我国现阶段实际的公路污染以及各种环境问题，探讨了加强公路环保及公路绿化问题，提出了相应的对策和建议。     

几种防水材料在高寒地区的应用比较

叙述了高寒地区屋面防水所存在的问题，比较了几种常见防水材料在材料特性，施工工艺、工程造价、存在问题诸方面的异同，并对保湿层内结露冻冰问题及漏水斗堵塞问题提出了相应的解决方案。     

木里县退耕还林工程建设

介绍了木里县退耕还林各项基本情况，剖析了其中存在的主要问题，针对问题，提出了相应的对策与建议。     

我省丘岗山地开发中存在的问题及解决途径

近两年来，我省丘岗山地开发得到了全省人民和各级党委、政府的热烈响应，取得了显著成效。但是，丘岗山地开发中出还存在一些问题，有些地方还比较严重，如因地制宜不够、优质种苗紧缺、技术服务跟不上、开发资金不足等，文章论述了这些问题，并提出了解决这些问题的途径。     

废物交换是实现循环经济的重要途径

近年来，我国经济迅速发展，但同时也产生了许多环境问题，特别是废物问题成了当今世界的严峻问题，对废物的处理和利用已日益成为环境科学亟待解决的问题之一。受到各国的重视。如何将这些废物资源化，一个较好的途径就是利用循环经济理论，在企业之间进行废物交换，更好地保护环境。     

内蒙古自治区飞播造林四十年

本文从内蒙古的基本情况，飞播造林的主要成就，采取的主要措施及当前在飞播造林中存在的主要问题等方面，论述了我区飞播造林四十年的发展历程，总结了取得的成绩，指出了面临的问题以及解决这些问题的办法，并对我区飞播事业的发展前景做了展望。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.